Apparatus for heating smokable material and article of smokable material

ABSTRACT

An apparatus is provided for enabling smokable material to be heated to volatize at least one component of the smokable material. In one example, the apparatus has a capacitive sensor arranged to sense a change in capacitance when an article of smokable material is associated with a housing of the apparatus in use. In another example, the apparatus has a resistive sensor arranged to provide a measure of electrical resistance when an article of smokable material is associated with a housing of the apparatus in use. A combination of capacitive and resistive sensing may be used in some examples. In another example, a sensor makes use of at least two different sensing techniques. There is also provided an article of smokable material having a non-metallic electrically conductive region for detection by a sensor of an apparatus arranged to cause heating of the smokable material.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional patentapplication No. 61/968,780, filed on Mar. 21, 2014, the entire contentof which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to apparatus arranged to heat smokablematerial and to an article of smokable material.

BACKGROUND

Smoking articles such as cigarettes, cigars and the like burn tobaccoduring use to create tobacco smoke. Attempts have been made to providealternatives to these articles that burn tobacco by creating productsthat release compounds without burning. Examples of such products areso-called heat-not-burn products which release compounds by heating, butnot burning, the material. The material may be for example tobacco orother non-tobacco products, which may or may not contain nicotine.

SUMMARY

According to a first aspect of the present invention, there is providedan apparatus for enabling smokable material to be heated to volatise atleast one component of said smokable material, the apparatus comprising:

a housing; and

a capacitive sensor arranged to sense a change in capacitance when anarticle of smokable material is associated with the housing in use.

In an exemplary embodiment, the capacitive sensor comprises anelectrode, the apparatus comprising a processor constructed and arrangedto sense a change in the capacitance of the electrode and an article ofsmokable material associated with the housing in use.

In an exemplary embodiment, the capacitive sensor comprises at least twoelectrodes, the apparatus comprising a processor constructed andarranged to sense a change in the capacitance of the at least twoelectrodes when an article of smokable material is associated with thehousing in use. In an exemplary embodiment, the at least two electrodesare arranged such that at least a portion of an article of smokablematerial associated with the housing in use can be positioned betweenthe at least two electrodes.

In an exemplary embodiment, the apparatus comprises circuitryconstructed and arranged so that the apparatus is only operated to causeheating of an article of smokable material associated with the housingin use if the change in the capacitance meets at least one predeterminedcriterion.

In an exemplary embodiment, the apparatus comprises circuitryconstructed and arranged so as to alternate between apply a chargingvoltage to the capacitive sensor to charge the capacitive sensor to arelatively high voltage and allowing the capacitive sensor to dischargeto a relatively low voltage, the circuitry being arranged so that theapparatus is only operated to cause heating of an article of smokablematerial associated with the housing in use if the number of transitionsbetween the relatively high voltage and the relatively low voltage onthe capacitive sensor in a predetermined time period is less than apredetermined number. In an exemplary embodiment, the predeterminednumber is the number of transitions between the relatively high voltageand the relatively low voltage on the capacitive sensor in thepredetermined time period when no article of smokable material isassociated with the housing.

In an exemplary embodiment, the apparatus comprises a resistive sensorarranged to provide a measure of electrical resistance when an articleof smokable material is associated with the housing in use.

In an exemplary embodiment, the apparatus comprises a heater operable toheat an article of smokable material received within the housing in use.

According to a second aspect of the present invention, there is providedan apparatus for enabling smokable material to be heated to volatise atleast one component of said smokable material, the apparatus comprising:

a housing; and

a resistive sensor arranged to provide a measure of electricalresistance when an article of smokable material is associated with thehousing in use.

In an exemplary embodiment, the resistive sensor comprises at least twoelectrodes, the apparatus comprising a processor constructed andarranged to provide a measure of electrical resistance using the atleast two electrodes when an article of smokable material is associatedwith the housing in use. In an exemplary embodiment, the at least twoelectrodes are arranged such that at least a portion of an article ofsmokable material associated with the housing in use can be positionedbetween and in contact with the at least two electrodes, the at leasttwo electrodes in use providing a measure of the electrical resistanceof said at least a portion of an article of smokable material.

In an exemplary embodiment, the apparatus comprises circuitryconstructed and arranged so that the apparatus is only operated to causeheating of an article of smokable material associated with the housingin use if the electrical resistance meets at least one predeterminedcriterion.

In an exemplary embodiment, the apparatus comprises a heater operable toheat an article of smokable material received within the housing in use.

According to a third aspect of the present invention, there is providedan apparatus for enabling smokable material to be heated to volatise atleast one component of said smokable material, the apparatus comprising:

a housing; and

a sensor arrangement constructed and arranged to identify an article ofsmokable material when associated with the housing in use by making useof at least two different sensing techniques.

In an exemplary embodiment, one of the at least two different sensingtechniques uses capacitive sensing and another of the at least twodifferent sensing techniques uses resistive sensing.

In an exemplary embodiment, one of the at least two different sensingtechniques uses electrical sensing and another of the at least twodifferent sensing techniques uses optical sensing. Suitable opticalsensing techniques include for example the use of and detection of barcodes (which may be the conventional linear type or the more recent twodimensional type), using for example some kind of optical emitter, suchas one or more LEDs (light emitting diodes), laser or the like, andcorresponding detector or detectors. Visible or non-visible light may beused, depending on for example the nature of the indicium or marker orthe like in use on the of smokable material.

In an exemplary embodiment, the apparatus comprises a heater operable toheat an article of smokable material received within the housing in use.

According to a fourth aspect of the present invention, there is providedan article of smokable material, the article having a non-metallicelectrically conductive region for detection by a sensor of an apparatusarranged to cause heating of the smokable material.

In an exemplary embodiment, the non-metallic electrically conductiveregion is in the form of a band of material that at least partlyencircles the article.

In an exemplary embodiment, the non-metallic electrically conductiveregion comprises carbon.

In an exemplary embodiment, the non-metallic electrically conductiveregion is a printed ink.

In some example embodiments, the smokable material article may bereceived (at least in part) within the housing. In such exampleembodiments, the apparatus may itself include a heater operable to heatthe article of smokable material received within the housing in use. Insome other example embodiments, the smokable material article maycontain the smokable material, for example in liquid or other form, incombination with a heater. In such example embodiments, the smokablematerial article with integral heater may be connected to the apparatusin use, with the apparatus typically containing a power supply for theheater.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 shows a perspective view of an example of an apparatus forheating a smokable material;

FIG. 2 shows a longitudinal cross-sectional view of an example of anapparatus for heating a smokable material;

FIG. 3 shows a perspective view of an example of electrodes with asmokable material article inserted therebetween;

FIG. 4 shows schematically an example of connection of electrodes tosensing circuitry;

FIG. 5 shows an example of a graph of voltage versus time;

FIG. 6 shows an example of the change of detected voltage over time whenno smokable material article is present and when a smokable materialarticle is present;

FIG. 7 shows a perspective view of an example of an electrode and asmokable material article;

FIG. 8 shows a longitudinal cross-sectional view of another example ofan apparatus for heating a smokable material;

FIG. 9 shows a perspective view of another example of electrodes with asmokable material article inserted therebetween;

FIG. 10 shows a longitudinal cross-sectional view of another example ofan apparatus for heating a smokable material;

FIG. 11 shows a perspective view of another example of electrodes with asmokable material article inserted therebetween;

FIG. 12 shows schematically another example of connection of electrodesto sensing circuitry;

FIG. 13 shows a schematic longitudinal cross-section of an example of asmokable material article;

FIG. 14 shows an example of tipping paper; and

FIG. 15 shows another example of tipping paper.

DETAILED DESCRIPTION

As used herein, the term “smokable material” includes materials thatprovide volatilised components upon heating, typically in the form of anaerosol. “Smokable material” includes any tobacco-containing materialand may, for example, include one or more of tobacco, tobaccoderivatives, expanded tobacco, reconstituted tobacco or tobaccosubstitutes. “Smokable material” also may include other, non-tobacco,products, which, depending on the product, may or may not containnicotine.

Referring to FIG. 1, there is shown a perspective view of an example ofan apparatus 1 arranged to heat smokable material to volatise at leastone component of said smokable material, typically to form an aerosolwhich can be inhaled. The apparatus 1 is a so-called “heat-not-burn”apparatus 1. The apparatus 1 in this example is generally elongate,having a generally elongate cylindrical outer housing 2 of circularcross-section. The outer housing 2 has an open end 3, sometimes referredto herein as the mouth end. The outer housing 2 may be formed of a heatinsulating material. A particularly suitable material is polyether etherketone (PEEK), though other plastics, including for exampleacrylonitrile butadiene styrene (ABS), or other heat insulatingmaterials, may be used. The outermost surface of the outer housing 2 mayhave a decorative coating, such as a metallic finish. The innermostsurface of the outer housing 2 may be coated, partially or fully, with amaterial that is a good heat conductor. By way of example, a metalcoating, such as of copper, may be used for this purpose.

FIG. 2 shows a cross-sectional view of an example of an apparatus 1 forheating a smokable material. The apparatus 1 has a heating chamber 4which in use contains the smokable material to be heated and volatised.The smokable material may be in the form of an article 5, formed of orcontaining smokable material, which can be removably inserted into theapparatus 1 by a user. The smokable material article 5 may be agenerally elongate cylinder, for example a cartridge or cassette or rod.The smokable material article 5 is in use inserted into the housing 2.An end of the smokable material article 5 projects out of the apparatus1 through the open end 3 of the housing 2, typically for connection to afilter or the like, which may be a separate item or provided with thesmokable material article 5, through which a user inhales in use.

The apparatus 1 further has an electronics/power chamber 6 which in thisexample contains electrical control circuitry 7 and a power source 8. Inthis example, the heating chamber 4 and the electronics/power chamber 6are adjacent each other along the longitudinal axis X-X of the apparatus1. In the example shown, the electronics/power chamber 6 is remote fromthe mouth end 3, though other locations are possible. The electricalcontrol circuitry 7 may include a controller, such as a microprocessorarrangement, configured and arranged to control the heating of thesmokable material and also to recognise or identify the smokablematerial article 5, as discussed further below. The electrical controlcircuitry 7 may in use receive a signal from for example a puff-actuatedsensor which is sensitive to for example changes in pressure or changesin rate of air flow that occur upon initiation of a draw on the smokablematerial article 5 by a user. The electrical control circuitry 7 canthen operate so as to cause heating of the smokable material article 5“on demand” when required. Various arrangements for a puff-actuatedsensor are available, including for example a thermistor, anelectro-mechanical device, a mechanical device, an optical device, anopto-mechanical device and a micro electro mechanical systems (MEMS)based sensor. As an alternative, the apparatus may have a manuallyoperable switch for a user to initiate a puff.

The power source 8 may be a battery, which may be a rechargeable batteryor a non-rechargeable battery. Examples of suitable batteries includefor example a lithium-ion battery, a nickel battery (such as anickel-cadmium battery), an alkaline battery and/or the like. Aparticularly preferred type of battery is a LiFePO₄ battery. The battery8 is electrically coupled to the one or more heating elements (to bediscussed further below) of the heating chamber 4 to supply electricalpower when required and under control of the electrical controlcircuitry 7 to heat the smokable material (as discussed, to volatize thesmokable material without causing the smokable material to burn). Inthis example, the battery 8 is contained within a printed circuit boardof the electrical control circuitry 7. In other examples, the battery 8and the electrical control circuitry 7 may be arranged differently, suchas for example arranged adjacent each other along the longitudinal axisX-X of the apparatus 1.

The heating chamber 4 is contained within a heater support sleeve 9,which is contained within the outer housing 2. In this example, theheater support sleeve 9 is a generally elongate cylinder of circularcross-section. In an example, the heater support sleeve 9 is adouble-walled or “vacuum” sleeve, having an outer cylindrical wall andan inner cylindrical wall which are joined to each other at each end andseparated by a small separation d. As just one example and to give anidea of scale, the heater support sleeve 9 may be around 50 mm long andhave an outer diameter of around 9 mm, and the separation d may bearound 0.1 mm to 0.12 mm or so. One of the functions of the heatersupport sleeve 9 in one example is to assist in heat-insulating theouter housing 2 from the heating chamber 4, so that the outer housing 2does not become hot or at least too hot to touch during use. The spacebetween the outer and inner cylindrical walls of the heater supportsleeve 9 may contain air. However, the space between the outer and innercylindrical walls of the heater support sleeve 9 is preferably evacuatedto improve the heat insulating properties of the heater support sleeve9. As an alternative, the space between the outer and inner cylindricalwalls of the heater support sleeve 9 may be filled with some otherinsulating material, including a suitable foam-type material forexample. The material of the heater support sleeve 9 is preferably suchthat the heater support sleeve 9 is rigid to provide structuralstability for the components mounted therein. An example of a suitablematerial is stainless steel. Other suitable materials include polyetherether ketone (PEEK), ceramics, glass, steel, aluminium, etc.

In one example of the apparatus 1, the heater support sleeve 9 containsat least one heating element 10 and may contain plural heating elementsor heater segments 10. There are preferably at least two heater segments10, though arrangements with other numbers of heater segments 10 arepossible. In the particular example shown, there are four heatersegments 10. In this example, the heater segments 10 align along orparallel to the longitudinal axis X-X of the heater support sleeve 9.The electrical control circuitry 7 and the power connections to theheater segments 10 are preferably arranged such that at least two, andmore preferably all, of the heater segments 10 can be poweredindependently of each other, so that selected zones of the smokablematerial article 5 can be independently heated, for example in turn(over time) or together (simultaneously) as desired. In this particularexample, the heater segments 10 are generally annular or cylindrical,having a hollow interior which in use contains the smokable materialarticle 5. In an example, the heater segments 10 may be made of aceramics material. Examples include alumina and aluminium nitride andsilicon nitride ceramics, which may be laminated and sintered. Theapparatus 1 has an on/off switch 11 projecting through the outer housing2 for operation by a user.

Different shapes and different configurations for the or each heatersegment 10 may be used. Moreover, other heating arrangements arepossible, including for example infrared heater segments 10, which heatby emitting infrared radiation, or resistive heating elements formed byfor example a resistive electrical winding around the heater segments10. Yet other different heating arrangements may be used.

It is sometimes desirable for the apparatus 1 to be able to identify orrecognise the particular smokable material article 5 that has beenintroduced into the apparatus 1 by a user. For example, in practice, theapparatus 1 as a whole, including in particular the heating arrangementand the heating control provided by the electrical control circuitry 7,will often be optimised for a particular arrangement of the smokablematerial article 5 (e.g. one or more of size, shape, particular smokablematerial, etc.) and it would be undesirable for the apparatus 1 to beused with smokable material or a smokable material article 5 having(significantly) different characteristics. In addition, if the apparatus1 can identify or recognise the particular smokable material article 5,or at least the general type of smokable material article 5, that hasbeen introduced into the apparatus 1, this can help eliminate or atleast reduce counterfeit or other non-genuine smokable material articles5 being used with the apparatus 1. The apparatus 1 may be arranged sothat it will only heat a smokable material article 5 that it recognises,and will not operate in conjunction with a smokable material article 5that it does not recognise. The apparatus 1 may be arranged so that itprovides some indication to the user that the smokable material article5 has not been recognised. This indication may be visual (for example awarning light, which may for example flash or be illuminatedcontinuously for a period of time) and/or audible (for example a warning“beep” or the like). Alternatively or additionally, the apparatus 1 maybe arranged so that for example it follows a first heating pattern whenit recognises a first type of smokable material article 5 and follows asecond, different heating pattern when it recognises a second type ofsmokable material article 5 (and optionally may provide yet furtherheating patterns for other types of smokable material article 5). Theheating patterns may differ in a number of ways, for example the rate ofdelivery of heat to the smokable material, the timing of various heatingcycles, which part(s) of the smokable material are heated first, etc.,etc. This enables the same apparatus 1 to be used with different basictypes of smokable material article 5 with minimal interaction requiredof the user.

In an example of an embodiment, the apparatus 1 is constructed andarranged to use capacitive sensing to sense a change in capacitance whenan article of smokable material 5 is received within the housing 2 inuse. In another example of an embodiment, the apparatus 1 is constructedand arranged to use resistive sensing to sense a smokable materialarticle 5 received within the housing 2. In another example of anembodiment, the apparatus 1 is constructed and arranged to use acombination of capacitive and resistive sensing to sense a smokablematerial article 5 received within the housing 2. In an example of anembodiment, the apparatus 1 senses a change in capacitance when asmokable material article 5 is received within the housing 2. Thecapacitance when a smokable material article 5 is received within thehousing 2 may in effect be compared with the capacitance when a smokablematerial article 5 is not present within the housing 2. In any of theseexamples, this enables some identification or recognition of aparticular smokable material article 5 received within the housing. Inan example of an embodiment, a smokable material article 5 is providedso as to be able to be sensed by a sensor of an apparatus 1 as describedherein. In a particular example of an embodiment, a smokable materialarticle 5 is provided with a strip or band or other marker or indiciumor indicia which can be sensed by a sensor of an apparatus 1 asdescribed herein.

In general, capacitive sensing as used herein operates by effectivelysensing a change in capacitance when the smokable material article 5 islocated within the apparatus 1. In effect, in an embodiment, a measureof the capacitance is obtained. If the capacitance meets one or morecriteria, it may be decided that the smokable material article 5 issuitable for use with the apparatus 1, which can then proceed to operateas normal to heat the smokable material. Otherwise, if the capacitancedoes not meet the one or more criteria, it may be decided that thesmokable material article 5 is not suitable for use with the apparatus1, and the apparatus 1 does not function to heat the smokable materialand/or may issue some warning message to the user.

In general, capacitive sensing as used herein may work in one of twoways. First, the apparatus 1 may be provided with (at least) oneelectrode which in effect provides one “plate” of a capacitor, with theother “plate” of the capacitor being provided by the smokable materialarticle 5 (or at least by some feature on the smokable material article5, such as the marker or indicium mentioned above and discussed furtherbelow). An example of this is shown schematically in FIG. 7, which showsa perspective view of just the electrode 70 and portions of a connectingwire 71 which connects to sensing circuitry in the apparatus 1, withoutthe other parts of the apparatus 1 being illustrated in FIG. 7. When thesmokable material article 5 is inserted into the apparatus 1, a measureof the capacitance formed by the combination of the electrode 70 of theapparatus 1 and the smokable material article 5 can be obtained, andthen compared to one or more criteria to determine whether the apparatus1 can then proceed to heat the smokable material.

As an alternative, the apparatus 1 may be provided with (at least) twoelectrodes, which in effect provide the pair of “plates” of a capacitor.When the smokable material article 5 is inserted into the apparatus 1,it is inserted between the two electrodes. As a result, the capacitanceformed between the two electrodes of the apparatus 1 changes. A measureof this capacitance formed by the two electrodes of the apparatus 1 canbe obtained, and then compared to one or more criteria to determinewhether the apparatus 1 can then proceed to heat the smokable material.

The example shown in FIG. 2 is an example of apparatus 1 that uses (atleast) two electrodes to allow capacitive sensing to sense a smokablematerial article 5 received within the housing 2. In particular, in thisexample, the apparatus 1 has two electrodes 12 located near the open end3 of the outer housing 2. The two electrodes 12 are curved, eachelectrode 12 being almost semi-circular in cross-section so as to definea generally circular opening into which the smokable material article 5passes when received in the housing 2. In the example shown, theelectrodes 12 extend somewhat longitudinally, generally parallel to thelongitudinal axis of the apparatus 1, so as to create a larger area ofoverlap of the electrodes 12 and therefore increase the effectivecapacitance. The electrodes 12 are connected to sensing circuitry 13 viaconnecting wires 14. The sensing circuitry 13 may be provided as part ofthe electrical control circuitry 7, for example as part of thecontroller, such as the microprocessor, described above, or as separatecircuitry. For the purposes of illustration, FIG. 3 shows a perspectiveview of just the electrodes 12 and portions of the connecting wires 14(without the other parts of the apparatus 1) with a smokable materialarticle 5 inserted therebetween. FIG. 4 shows schematically theconnection of the electrodes 12 to the sensing circuitry 13. It isemphasised that the sensing circuitry 13 may be separate from orintegrally formed with the electrical control circuitry 7, for exampleas part of the controller, such as the microprocessor, and indeed thefunction of the sensing circuitry 13 may be provided entirely by thecontroller, such as the microprocessor. An example of sensing circuitry13 is shown schematically in FIG. 4, it being understood that otherarrangements for the sensing circuitry 13 are possible, whether as partof the controller, such as the microprocessor, of the apparatus 1 or asseparate circuitry.

In this example, the combination of the electrodes 12 and the sensingcircuitry 13 provides a capacitive sensor 15. In this example, thesensing circuitry 13 alternates between supplying voltage to one of thecapacitor electrodes 12 and allowing voltage to drain from the one ofthe capacitor electrodes 12. The other of the capacitor electrodes 12 isearthed (for example by being electrically connected to the outerhousing 2 of the apparatus 1).

In more detail, in an example, the sensing circuitry 13 has an op-amp(operational amplifier) or other differential amplifier 16 having anon-inverting input 17 and an inverting input 18. An output 19 of theop-amp 16 is connected to an inverter 20. The non-inverting input 17 isconnected to the one of the capacitor electrodes 12. The non-invertinginput 17 is also connected via a resistor 21 to the output of theinverter 20. The output of the inverter 20 is also connected to avoltage control portion 21 of the sensing circuitry 13. The voltagecontrol portion 21 passes the output of the inverter 20 to control afirst switch 22 and, via a second inverter 23, to control a secondswitch 24. The outputs of the first and second switches 22,24 areconnected to the inverting input 18 of the op-amp 16. The input of thefirst switch 22 is at a relatively high voltage V_(DD) _(_) _(SCALED)and the input of the second switch 24 is at a relatively low voltageV_(DD)/4.

In an example, the operation of this example of the apparatus 1 is asfollows. First, when the apparatus 1 is in a state where there is nosmokable material article 5 inserted in the apparatus 1, the apparatus 1periodically makes a calibration of the capacitive sensor 15 provided bythe combination of the sensing circuitry 13 and capacitor electrodes 12to establish a baseline value, against which subsequent measurementswill be assessed. In particular, preferably under control of thecontroller of the electrical control circuitry 7 of the apparatus 1, ahigh “excitation” voltage is applied to the one of the electrodes 12.This causes the charge and therefore voltage on the one of theelectrodes 12 to increase, the increase being at a characteristic ratedefined by the resistance and capacitance present in the relevant partsof the capacitive sensor 15. This high “excitation” voltage is alsoapplied to the voltage control portion 21, which causes the first switch22 to close and the second switch 24 to open so that the input voltageV_(DD) _(_) _(SCALED) of the first switch 22 is applied to the invertinginput 18 of the op-amp 16.

Once the voltage on the one of the electrodes 12, which is applied tothe non-inverting input 17 of the op-amp 16, reaches a predeterminedvalue (in this example, the input voltage V_(DD) _(_) _(SCALED) of thefirst switch 22), the output of the op-amp 16 switches. This causes thefirst switch 22 to open and the second switch 24 to close so that theinput voltage V_(DD)/4 of the second switch 24 is applied to theinverting input 18 of the op-amp 16. At the same time, the charge on theone of the electrodes 12 drains through the resistor 21, causing thevoltage on the one of the electrodes 12 to fall at a characteristic ratedefined by the resistance and capacitance present in the relevant partsof the capacitive sensor 15. Once the voltage on the one of theelectrodes 12 falls to a second predetermined value (in this example,the input voltage V_(DD)/4 of the second switch 24), the output of theop-amp 16 switches back again and the process is repeated.

The effect of this can be seen in FIG. 5. FIG. 5 shows a graph ofvoltage v. time. The bold lines show a square wave type voltage thatalternates between applying a high voltage to the one of the electrodes12 to charge the electrode 12 and removing that voltage to allow thecharge on the one of the electrodes 12 to drain away. (In the exampleshown, when ACMPOUT is high, V_(DD)/4 is selected as the referencevoltage, and, due to the inverter 20, the one of the electrodes 12starts to discharge. When the capacitor voltage drops below V_(DD)/4,the ACMPOUT level toggles to a low state and V_(DD) _(_) _(SCALED) isselected as the reference and the charge on the one of the electrodes 12starts to increase. When the capacitor voltage again reaches V_(DD) _(_)_(SCALED), the ACMPOUT toggles (goes high), V_(DD)/4 is again selectedas a reference voltage, and the cycle repeats.) The alternating chargingand discharging of the one of the electrodes 12 is indicated by a lightgrey line. It can be seen that the increase and then decay of the chargeor voltage on the one of the electrodes 12 each takes place at acharacteristic rate.

Then, upon user initiation, i.e. when the user has inserted a smokablematerial article 5 into the apparatus 1 and initiates a session (forexample, by operating some actuator switch and/or by use of apuff-actuated sensor), the controller of the apparatus 1 reads thecapacitive sensor 15 in a similar way. In particular, again, preferablyunder control of the controller of the electrical control circuitry 7 ofthe apparatus 1, a high “excitation” voltage is applied to the one ofthe electrodes 12. This causes the charge and therefore voltage on theone of the electrodes 12 to increase, the increase being at acharacteristic rate defined by the resistance and capacitance present inthe relevant parts of the capacitive sensor 15. This high “excitation”voltage is also applied to the voltage control portion 21, which causesthe first switch 22 to close and the second switch 24 to open so thatthe input voltage V_(DD) _(_) _(SCALED) of the first switch 22 isapplied to the inverting input 18 of the op-amp 16. Once the voltage onthe one of the electrodes 12, which is applied to the non-invertinginput 17 of the op-amp 16, reaches a predetermined value (in thisexample, the input voltage V_(DD) _(_) _(SCALED) of the first switch22), the output of the op-amp 16 switches. This causes the first switch22 to open and the second switch 24 to close so that the input voltageV_(DD)/4 of the second switch 24 is applied to the inverting input 18 ofthe op-amp 16. At the same time, the charge on the one of the electrodes12 drains through the resistor 21, causing the voltage on the one of theelectrodes 12 to fall at a characteristic rate defined by the resistanceand capacitance present in the relevant parts of the capacitive sensor15. Once the voltage on the one of the electrodes 12 falls to a secondpredetermined value (in this example, the input voltage V_(DD)/4 of thesecond switch 24), the output of the op-amp 16 switches back again andthe process is repeated.

In this case, because the smokable material article 5 is present betweenthe electrodes 12, the capacitance of the capacitive sensor 15 isdifferent. This means that the increase and decrease of voltage on theone of the electrodes 12 occurs at a different rate (and indeed with adifferent profile). This can be seen in FIG. 6, in which the upper traceshows the change of detected voltage on the one of the electrodes 12when no smokable material article 5 is present (as in FIG. 5) and thelower trace shows the change of detected voltage on the one of theelectrodes 12 when a smokable material article 5 is present between theelectrodes 12. As can be seen, when a smokable material article 5 ispresent between the electrodes 12, in this case the capacitance ishigher and so the rate of increase of voltage and likewise the rate ofdecrease of voltage is lower when smokable material article 5 is presentbetween the electrodes 12.

This difference in capacitance when a smokable material article 5 is oris not present between the electrodes 12 can be detected in a number ofdifferent ways to determine whether a smokable material article 5 ispresent, and in particular whether a correct or appropriate smokablematerial article 5 is present. For example, the difference in thevoltage trace, shown schematically in the upper and lower parts of FIG.6, can be used to obtain a measure of the value of the capacitance whena smokable material article 5 is present between the electrodes 12. Inanother example, the controller of the electrical control circuitry 7 ofthe apparatus 1 counts how many transitions (from high voltage to lowvoltage say) occur in a given time period. Because the rates of chargeand discharge are related to the capacitance present in the capacitivesensor 15, the number of transitions that occur in a given time arerelated to the capacitance present: a higher capacitance, such as when asmokable material article 5 is present, leads to fewer transitions in agiven time period. The controller of the electrical control circuitry 7of the apparatus 1 compares the number of transitions in a given timeperiod with that obtained during the calibration process (i.e. when nosmokable material article 5 was present). If the number of transitionsover a certain time period is below some predetermined threshold, orfalls within a predetermined range, then the smokable material article 5is considered genuine, and the session is allowed to complete to resultin the smokable material article 5 being heated. If however the numberof transitions over a certain time period is above the predeterminedthreshold or does not fall within the predetermined range, then thesmokable material article 5 is not considered genuine and a heatingsession will not start; optionally, the user can be notified separately,as mentioned above. As an alternative, rather than using an absolutethreshold number for the number of transitions (from high voltage to lowvoltage say) say, the threshold number for the number of transitionswhen a smoking material article 5 is present in the apparatus 1 may be acertain proportion or percentage of the number of transitions when asmoking material article 5 is not present in the apparatus 1 (as in thecalibration phase discussed above). It will be understood that thenumber of transitions between a maximum voltage and a minimum voltage onthe capacitive sensor over a certain time period is a measure of therate of charge/discharge of the capacitive sensor 15. In a specificexample, and without limitation, some nominal values are V_(DD) _(_)_(SCALED)=2.25V, V_(DD)/4=0.56V, the measurement time is 0.1 second, andthe number transitions per measurement is 1000. In a specific actualexample during testing, the number of transitions per measurement whenno smoking material article 5 is present in the apparatus 1 was 1100whereas the number of transitions per measurement when a smokingmaterial article 5 is present in the apparatus 1 was 1050.

It may be noted that apparatus 1 that has (at least) two electrodes 12for capacitive sensing of the smokable material article 5 mayalternatively operate as described above where one electrode 12 ineffect provides one “plate” of a capacitor, with the other “plate” ofthe capacitor being provided by the smokable material article 5 (or atleast by some feature on the smokable material article 5, such as themarker or indicium mentioned above and discussed further below). (Thisis in contrast to the specific example described above where thecapacitance between the two electrodes 12 is sensed.) When the smokablematerial article 5 is inserted into the apparatus 1, a measure of thecapacitance formed by the combination of the electrode 12 of theapparatus 1 and the smokable material article 5 can be obtained, andthen compared to one or more criteria to determine whether the apparatus1 can then proceed to heat the smokable material. Having pluralelectrodes 12 spaced around the open end 3 of the apparatus 1 for thispurpose is of advantage in that the orientation of the smokable materialarticle 5 around the longitudinal axis X-X in the apparatus 1 is lessimportant, as in general at least one of the electrodes 12 will be closeenough to the smokable material article 5 sense the capacitancesufficiently.

In the specific example of FIGS. 2 to 4, the two electrodes 12 aregenerally or almost semi-circular and face each other on opposite sidesof the outer housing 2 to define the generally circular opening intowhich the smokable material article 5 passes when received in thehousing 2. Different shapes and arrangements for the electrodes 12 arepossible.

For example, FIGS. 8 and 9 show another example of apparatus 801 thatuses (at least) two electrodes 812 located near the open end 803 of theouter housing 802 to allow capacitive sensing to sense a smokablematerial article 805 received within the housing 802. Components andcircuitry that are the same as or at least functionally similar tocorresponding items in the example of FIGS. 2 and 3 have similarreference numerals, but increased by “800”. Thus, the example apparatus801 shown in FIGS. 8 and 9 has a heating chamber 804, anelectronics/power chamber 806 containing electrical control circuitry807 and a power source 808, a heater support sleeve 809, plural heatingelements or heater segments 810, and an on/off switch 811, etc., all ofwhich may be the same as or at least functionally similar to thecorresponding components of the example shown schematically in FIGS. 2to 4. Other heating arrangements are possible, including for exampleinfrared heater segments 810, which heat by emitting infrared radiation,or resistive heating elements formed by for example a resistiveelectrical winding around the heater segments 810. Yet other differentheating arrangements may be used.

In the example of FIGS. 8 and 9, the two electrodes 812 areinterdigitated. As with the example of FIGS. 2 and 3, the electrodes 812are connected to sensing circuitry 813 via connecting wires 814. Thesensing circuitry 813 may be provided as part of the electrical controlcircuitry 807, for example as part of the controller, such as themicroprocessor, described above, or as separate circuitry. For thepurposes of illustration, FIG. 9 shows a perspective view of just theelectrodes 812 (without the other parts of the apparatus 801) with asmokable material article 805 inserted therebetween. As in the exampleabove, the combination of the electrodes 812 and the sensing circuitry813 provides a capacitive sensor. In this example, the sensing circuitry813 alternates between supplying voltage to one of the capacitorelectrodes 812 and allowing voltage to drain from the one of thecapacitor electrodes 812. The other of the capacitor electrodes 812 isearthed (for example by being electrically connected to the outerhousing 802 of the apparatus 801). The capacitance provided by theelectrodes 812, and how that capacitance changes when a smokablematerial article 805 is received within the housing 802, is monitored soas to enable a determination to be made as to whether or not thesmokable material article 805 is “genuine”. This may be carried outsimilarly to the main example described above, i.e. by alternatingcharging the one of the capacitor electrodes 812 and draining of voltagefrom the one of the capacitor electrodes 812, both during a calibrationphase prior to a smokable material article 805 being received within thehousing 802 and then when a smokable material article 805 is receivedwithin the housing 802, and counting the number of transitions (fromhigh voltage to low voltage say) that occur in a given time period.Again, however, other methods may be used.

As stated, in this example of FIGS. 8 and 9, the two electrodes 812 areinterdigitated. That is, in this example, each electrode 812 isgenerally annular and has a number of castellations or “fingers” 820extending generally parallel to the longitudinal axis of the apparatus801. The electrodes 812 are mounted in the outer housing 802 of theapparatus 801 so that the fingers 820 of one electrode 812 lie betweenthe fingers 820 of the other electrode 820, so as to create a large areaof overlap of the electrodes 812 and therefore increase the effectivecapacitance. In this example, the fit between the fingers 820 of therespective electrodes 812 is a snug fit, though, whilst this ispreferred, a loose (non-contact) fit is also possible.

FIGS. 10 to 12 show schematically an example of an embodiment in whichresistive sensing is used to sense a smokable material article receivedwithin the housing. Components and circuitry that are the same as or atleast functionally similar to corresponding items in the example ofFIGS. 2 and 3 have similar reference numerals, but increased by “1000”.Thus, the example apparatus 1001 shown in FIGS. 10 to 12 has an outerhousing 1002 having an open end 1003, a heating chamber 1004 whichreceives a smokable material article 1005 in use, an electronics/powerchamber 1006 containing electrical control circuitry 1007 and a powersource 1008, a heater support sleeve 1009, plural heating elements orheater segments 1010, and an on/off switch 1011, etc., all of which maybe the same as or at least functionally similar to the correspondingcomponents of the example shown schematically in FIGS. 2 to 4. Otherheating arrangements are possible, including for example infrared heatersegments 1010, which heat by emitting infrared radiation, or resistiveheating elements formed by for example a resistive electrical windingaround the heater segments 1010. Yet other different heatingarrangements may be used.

In the example of FIGS. 10 to 12, the apparatus 1001 has at least twoelectrically conductive resistance contacts or electrodes 1050 locatednear the open end 1003 of the outer housing 1002. The two electrodes1050 are curved, each electrode 1050 being almost semi-circular incross-section so as to define a generally circular opening into whichthe smokable material article 1005 passes when received in the housing1002. The two electrodes 1050 may be formed of a relatively elastic orspringy material and may be arranged so as to be biased slightlyinwardly, towards each other. This helps to ensure a good physicalcontact with a smokable material article 1005 when the smokable materialarticle 1005 is introduced into the apparatus 1002.

The electrodes 1050 are connected to sensing circuitry 1013 viaconnecting wires 1014. The sensing circuitry 1013 may be provided aspart of the electrical control circuitry 1007, for example as part ofthe controller, such as the microprocessor, described above, or asseparate circuitry. For the purposes of illustration, FIG. 11 shows aperspective view of just the electrodes 1050 (without the other parts ofthe apparatus 1001) with a smokable material article 1005 insertedtherebetween. The combination of the electrodes 1050 and the sensingcircuitry 1013 provides a resistive sensor.

The resistance effectively measured by the electrodes 1050, and how thatresistance changes when a smokable material article 1005 is receivedwithin the housing 1002, is monitored so as to enable a determination tobe made as to whether or not the smokable material article 1005 is“genuine”. This may be carried out by for example the electrical controlcircuitry 1007 causing a reference voltage V_(dd) to be applied acrossthe electrodes 1050 and detecting the current that is output. A highcurrent indicates that the resistance is low and a small currentindicates that the resistance is high. An absolute measure of theresistance may be obtained. Again, however, other methods may be used.

In another example of an embodiment, a combination of capacitive andresistive sensing may be used, using a combination of any of theexamples described above. In general, this permits more informationabout the smokable material article to be obtained. This enables a moreprecise identification of the smokable material article to be obtainedand/or allows more information effectively to be encoded in the smokablematerial article. In certain embodiments, this also provides for someredundancy in that if for some reason one of the capacitive sensing andthe resistive sensing fails, then the other may be used to identify thesmokable material article which has been introduced into the apparatus.The capacitive sensing and the resistive sensing may be carried outusing the same electrode or electrodes in the apparatus or thecapacitive sensing and the resistive sensing may use their ownrespective dedicated electrode or electrodes.

The electrode or electrodes described above, whether in the form of forexample capacitive pads for capacitive sensing or resistive contacts forresistive sensing, are in general electrically conductive. In the caseof an electrode or electrodes for capacitive sensing, the electrode orelectrodes are preferably mechanically mounted in the body of theapparatus or housing so as to be electrically isolated from the smokablematerial article when the smokable material article is received in orconnected to the apparatus in use. In the case of an electrode orelectrodes for resistive sensing, the electrode or electrodes arepreferably mechanically mounted in the body of the apparatus or housingso as to make physical contact with the smokable material article whenthe smokable material article is received in or connected to theapparatus in use. Suitable materials for the electrode or electrodesinclude copper or copper-containing alloys, including for example acopper foil in the case of capacitive sensing and beryllium-copper inthe case of resistive sensing.

In FIG. 13, there is shown a schematic longitudinal cross-section of anexample of a smokable material article 130 which is provided or formedwith some marker or indicium 131, examples of which will be describedfurther below. The smokable material article 130 may be used inconjunction with at least some of the examples of apparatus for heatingthe smokable material as described herein. The arrangement of theindicium 131 may differ for, and be optimised differently for, theparticular heating apparatus.

The smokable material article 130 has a rod 132 of the smokablematerial. As mentioned above, the smokable material may include forexample any tobacco-containing material and may, for example, includeone or more of tobacco, tobacco derivatives, expanded tobacco,reconstituted tobacco or tobacco substitutes. “Smokable material” alsomay include other, non-tobacco, products, which, depending on theproduct, may or may not contain nicotine. The rod 132 of the smokablematerial is adjacent an open tube filter 133. The rod 132 and the filter133 are assembled and held together by being rolled in tipping paper 134in a manner known per se.

In the example shown, the marker or indicium 131 is provided on thetipping paper 134. In the example shown, the indicium 131 is in the formof a band of material which, in the assembled smokable material article130, completely encircles the smokable material article 130. Thisarrangement facilitates the measuring of the properties of the indicium131 by the examples of the heating apparatus described above as theparticular orientation of the smokable material article 130 within theheating apparatus is not important. Other arrangements are possible. Forexample, it may not be necessary in all cases for the indicium 131 tocompletely encircle the smokable material article 130, and instead theindicium 131 may be formed as a different, non-continuous pattern, suchas a regular or irregular checkerboard pattern or as a regular orirregular spacing of bands or strips encircling the smokable materialarticle 130. FIG. 14 shows an example of the tipping paper 134 prior toassembly of the smokable material article 130 in which the tipping paper134 has a single band of the indicium 131. FIG. 15 shows an example ofthe tipping paper 134 prior to assembly of the smokable material article130 in which the tipping paper 134 is effectively double width and has apair of bands of the indicium 131 at opposite edges. During manufacture,the double width tipping paper 134 is cut through the centre as pairs ofsmokable material articles 130 are formed.

To give an idea of scale, in a specific example the rod 132 of thesmokable material has a length of around 53 mm, the filter 133 has alength of 30 mm, and the tipping paper may be 35 mm wide (in a directionparallel to the length of the smokable material article 130). Theindicium 131 may have a width (again in a direction parallel to thelength of the smokable material article 130) of around 4 mm. It ispreferred that the thickness of the indicium 131 is small so as not tointerfere with the manufacturing process used for the smokable materialarticle or to make it difficult to insert the smokable material articleinto the heating apparatus. For example, the thickness may be in theapproximate range 0.03 mm to 0.3 mm, and more preferably between around0.03 to 0.05 mm. Indeed, if impregnated into the surface of the smokablematerial article, the indicium 131 may effectively have no thickness atall. On the other hand, there may be specific applications where aminimum thickness is preferred in order to enable satisfactory sensingto be achieved.

The marker or indicium 131 may be formed in a number of different ways,and be formed of a number of different materials, depending on theparticular sensing arrangement of the heating apparatus with which thesmokable material article 130 is intended to be used. The indicium 131may for example be provided externally of the smokable material article130, internally of the smokable material article 130, both externallyand internally of the smokable material article 130, and/or impregnatedinto the material of the tipping paper 134. (The indicium 131 is shownin exaggerated form in FIG. 13 for the purposes of illustration.) Whereresistive sensing is used (whether on its own or in combination withsome other sensing, such as capacitive sensing), the indicium 131 ispreferably provided on the outside of the smokable material article 130so that the resistive sensing electrodes of the heating apparatus canmake good electrical contact with the indicium 131. Where capacitivesensing is used, the indicium 131 may be provided internally orexternally of the smokable material article 130. The indicium 131 may beprovided internally and externally of the smokable material article 130,and/or separate indicia 131 may be provided internally and externally ofthe smokable material article 130. The marker or indicium 131 may beliterally “marked on” the smokable material article 130, such as byprinting. Alternatively, the marker or indicium 131 may be provided inor on the smokable material article 130 by other techniques, such asbeing formed integrally with the smokable material article 130 duringmanufacture.

In certain examples, and depending on the nature of the sensing that isused to sense and identify the smokable material article 130, theindicium 131 may be formed of an electrically conductive material. Theindicium 131 may be for example a conductive ink. The ink may be printedonto the tipping paper 134, using for example a rotogravure printingmethod, screen printing, ink jet printing, or any other suitableprocess.

In use, particularly in the context of a heating apparatus that uses acapacitive sensor arranged to sense a change in capacitance when asmokable material article 130 is associated with the heating apparatus,and in particular a heating apparatus that uses (at least) twoelectrodes which in effect provide the pair of “plates” of a capacitor,the following considerations are relevant. The smokable material article130, with its electrically conductive indicium or marker 131, createsits own circuit, electrically coupling one sensor electrode with theother. The effectiveness and result of this coupling is affected by theinherent electrical resistance R_(i) and capacitance C of the smokablematerial article 130 and/or the indicium 131 in particular. Theelectrical resistance R_(i) is in general determined principally by forexample the type of ink and formulation chosen for the indicium 131 andby the thickness and width of the indicium 131. Accordingly, the choiceof ink for the indicium 131, as well as its application thickness,provide a way of controlling the R_(i) characteristic over a wide range.The capacitance C is in general determined principally by the axialwidth of the indicium 131 and the distance of the indicium 131 from theelectrodes of the heating apparatus. This distance is in turn determinedby the spacing of the electrodes from each other and the thickness (e.g.diameter) of the smokable material article 130. Accordingly, thecoupling or “C” characteristic capacitive coupling between the detectorelectrodes and the indicium 131 on the smokable material article 130 canbe determined or controlled through the “fit” of the smokable materialarticle 130 in the heating apparatus, by for example appropriatelysetting the thickness or diameter of the smokable material article 130and by controlling the axial widths of the detector electrodes and ofthe indicium 131.

A particularly suitable material has been found to be a non-metallicconductive ink, that is an ink that is electrically conductive but whichcontains no metallic materials, or at least contains substantially nometallic materials. The ink may contain carbon for example, which may bein the form of graphite. The ink may therefore be a carbon-basednon-metallic electrically conductive ink. The weight resistivity of theink in a particular example may be in the range approximately 30,000 to300,000 Ohm-gram/m². Specific values of the weight resistivity ofexamples that have been found to be particularly suitable includeapproximately 38,000 Ohm-gram/m², 150,000 Ohm-gram/m² and 290,000Ohm-gram/m².

In one particular example, the ink may primarily comprise or consist ofa graphite powder and a resin that acts as a binder. The ink may usegraphite in an assortment of large and small particle sizes, of whichthe larger particles form the main path for electrical conduction withthe smaller particles “filling in” the gaps between the largerparticles. The use of larger sized particles helps to improve electricalconductivity by reducing the number of individual contact points betweenparticles. In another example, the ink may have a crystal structure thatuses carbon nano tubes.

It has been found that suitable inks for this purpose include theCI-2001 and CI-2004 conductive carbon inks supplied by EngineeredMaterials Systems, Inc. of Ohio, USA. These inks are intended for use inprinted electronics, such as on printed circuit boards or the like, forexample to provide physical and environmental protection at contactareas and to adjust for electrical resistance requirements.

Compared to other techniques, including some techniques known in theprior art, embodiments of the present invention have a number ofadvantages. The sensing arrangements provide a good signal-to-noiseratio, particularly in the case of capacitive sensing. This is ofparticular benefit in a battery-powered device as less electrical poweris consumed in processing the signals and a more accurate determinationcan be made more quickly. Moreover, as a generality, there will be amanufacturing tolerance during manufacture of smokable material articlessuch that the outside diameter of the smokable material articles willvary over a range. Such variation may in practice be of the order of 2%to 5% or so for example. In a specific case, the diameter of thesmokable material articles may vary from around 5.3 mm to 5.45 mm. Suchvariations are accommodated well by the present sensing arrangements,including in particular the various capacitive sensing arrangementsdisclosed herein. This is important as it minimises the number of “falsenegatives” that may otherwise occur whereby a genuine smokable materialarticle is inadvertently rejected. The present sensing arrangements mayuse fewer electrical components, with fewer input/output connections,than some other techniques.

In order to address various issues and advance the art, the entirety ofthis disclosure shows by way of illustration and example variousembodiments in which the claimed invention may be practised and whichprovide for a superior apparatus arranged to heat but not burn smokablematerial. The advantages and features of the disclosure are of arepresentative sample of embodiments only, and are not exhaustive and/orexclusive. They are presented only to assist in understanding and teachthe claimed and otherwise disclosed features. It is to be understoodthat advantages, embodiments, examples, functions, features, structuresand/or other aspects of the disclosure are not to be consideredlimitations on the disclosure as defined by the claims or limitations onequivalents to the claims, and that other embodiments may be utilisedand modifications may be made without departing from the scope and/orspirit of the disclosure. Various embodiments may suitably comprise,consist of, or consist in essence of, various combinations of thedisclosed elements, components, features, parts, steps, means, etc. Thedisclosure may include other inventions not presently claimed, but whichmay be claimed in future.

1. An apparatus for enabling smokable material to be heated to volatizeat least one component of said smokable material, the apparatuscomprising: a housing; and a capacitive sensor arranged to sense achange in capacitance when an article of smokable material has beenintroduced into the housing in use to enable the article of smokablematerial to be identified.
 2. An apparatus according to claim 1, whereinthe capacitive sensor comprises an electrode, the apparatus comprising aprocessor constructed and arranged to sense a change in the capacitanceof the electrode and an article of smokable material introduced into thehousing in use.
 3. An apparatus according to claim 1, wherein thecapacitive sensor comprises at least two electrodes, the apparatuscomprising a processor constructed and arranged to sense a change in thecapacitance of the at least two electrodes when an article of smokablematerial is introduced into the housing in use.
 4. An apparatusaccording to claim 3, wherein the at least two electrodes are arrangedsuch that at least a portion of an article of smokable materialintroduced into the housing in use can be positioned between the atleast two electrodes.
 5. An apparatus according to claim 1, comprisingcircuitry constructed and arranged so that the apparatus is onlyoperated to cause heating of an article of smokable material introducedinto the housing in use if the change in the capacitance meets at leastone predetermined criterion.
 6. An apparatus according to claim 1,comprising circuitry constructed and arranged so as to alternate betweenapply a charging voltage to the capacitive sensor to charge thecapacitive sensor to a relatively high voltage and allowing thecapacitive sensor to discharge to a relatively low voltage, thecircuitry being arranged so that the apparatus is only operated to causeheating of an article of smokable material introduced into the housingin use if the number of transitions between the relatively high voltageand the relatively low voltage on the capacitive sensor in apredetermined time period is less than a predetermined number.
 7. Anapparatus according to claim 6, wherein the predetermined number is thenumber of transitions between the relatively high voltage and therelatively low voltage on the capacitive sensor in the predeterminedtime period when no article of smokable material introduced into thehousing.
 8. An apparatus according to claim 1, comprising a resistivesensor arranged to provide a measure of electrical resistance when anarticle of smokable material is introduced into the housing in use. 9.An apparatus according to claim 1, comprising a heater operable to heatan article of smokable material received within the housing in use. 10.An apparatus for enabling smokable material to be heated to volatize atleast one component of said smokable material, the apparatus comprising:a housing; and a resistive sensor arranged to provide a measure ofelectrical resistance when an article of smokable material has beenintroduced into the housing in use to enable the article of smokablematerial to be identified.
 11. An apparatus according to claim 10,wherein the resistive sensor comprises at least two electrodes, theapparatus comprising a processor constructed and arranged to provide ameasure of electrical resistance using the at least two electrodes whenan article of smokable material is introduced into the housing in use.12. An apparatus according to claim 11, wherein the at least twoelectrodes are arranged such that at least a portion of an article ofsmokable material introduced into the housing in use can be positionedbetween and in contact with the at least two electrodes, the at leasttwo electrodes in use providing a measure of the electrical resistanceof said at least a portion of an article of smokable material.
 13. Anapparatus according to claim 1, comprising circuitry constructed andarranged so that the apparatus is only operated to cause heating of anarticle of smokable material introduced into the housing in use if theelectrical resistance meets at least one predetermined criterion.
 14. Anapparatus according to claim 1, comprising a heater operable to heat anarticle of smokable material received within the housing in use.
 15. Anapparatus for enabling smokable material to be heated to volatize atleast one component of said smokable material, the apparatus comprising:a housing; and a sensor arrangement constructed and arranged to identifyan article of smokable material when associated with the housing in useby making use of at least two different sensing techniques.
 16. Anapparatus according to claim 15, wherein one of the at least twodifferent sensing techniques uses capacitive sensing and another of theat least two different sensing techniques uses resistive sensing.
 17. Anapparatus according to claim 15, wherein one of the at least twodifferent sensing techniques uses electrical sensing and another of theat least two different sensing techniques uses optical sensing.
 18. Anapparatus according to claim 15, comprising a heater operable to heat anarticle of smokable material received within the housing in use.
 19. Anarticle of smokable material, the article having a non-metallicelectrically conductive region for detection by a sensor of an apparatusarranged to cause heating of the smokable material.
 20. An articleaccording to claim 19, wherein the non-metallic electrically conductiveregion is in the form of a band of material that at least partlyencircles the article.
 21. An article according to claim 19, wherein thenon-metallic electrically conductive region comprises carbon.
 22. Anarticle according to claim 19, wherein the non-metallic electricallyconductive region is a printed ink.